Scaffolding tube clamps

ABSTRACT

A clamp for securement to a cylindrical body such as scaffold tubing has first and second curved body portions hinged to each other to form a generally circular enclosure. A clasp for coupling the first and second curved body portions has a bolt fixed to one curved body portion and a rotatable housing. The housing has a peripheral groove to slidingly receive the bolt and is coupled to the other curved body portion. The housing has an access opening to receive the bolt into the peripheral groove and the bolt is captured in the peripheral groove when the housing is rotated. The housing is rotatable about a post which is fixed to the other curved body portion and has an opening to receive the post that is eccentric to the geometric center of the housing so that a passage formed between the peripheral groove and the post varies in width about the periphery of the housing. This variable width allows the housing to be tightened gradually on the bolt.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 U.S.C. 371 to International Patent Application Serial Number PCT/CA2007/000277, filed 22 Feb. 2007, claiming priority to Canadian Patent Application Number 2,537,674 filed 27 Feb. 2006, entitled “SCAFFOLDING TUBE CLAMPS,” the entirety of which is incorporated herein by reference.

FIELD OF INVENTION

This invention relates to clamps used to couple cylindrical bodies, more particularly, cylindrical bodies in the form of tubes used to erect scaffolding at building sites.

BACKGROUND OF THE INVENTION

Many styles of clamps are known for coupling scaffold tubes. The main styles are known as “nut and bolt” as exemplified by U.S. Pat. No. 6,786,302, and “wedge clamp” as exemplified by U.S. Pat. No. 6,789,647. Each of the aforementioned clamp styles suffers from specific disadvantages which this invention is intended to overcome.

An object of this invention is to provide a secure means of coupling to a cylindrical body which is easy to use and reliable but which also will accommodate small variations in the outer diameter of scaffold tubes from different suppliers.

SUMMARY OF THE INVENTION

In accordance with this invention, there is provided a clamp for securement to at least one cylindrical body, the clamp having first and second curved body portions hinged to each other to form a generally circular enclosure to receive the cylindrical body and a clasp for releasably coupling the first and second curved body portions. The clasp has a bolt fixed to one curved body portion and a rotatable housing defining a peripheral groove to slidingly receive the bolt is coupled to the other curved body portion. The housing has an access opening to receive the bolt into the peripheral groove and the bolt is captured in the peripheral groove when the housing is rotated. The housing is rotatable about a post which is fixed to the other curved body portion and has an opening to receive the post that is eccentric to the geometric center of the housing so that a passage formed between the peripheral groove and the post varies in width about the periphery of the housing. This variable width allows the housing to be tightened gradually on the bolt. To minimize any slipping, the post itself is eccentric to the opening in the housing.

The clamp may be used as a fence clamp for securing to a single cylindrical body or tube, or it may be used in pairs to couple more than one tube in which case, the clamp pairs may be secured by welding or rotatably coupled together to vary the angle therebetween and accommodate tubes or other cylindrical bodies which are not orthogonal.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to better understand the invention, a preferred embodiment is described below with reference to the accompanying drawings, in which:

FIG. 1 is a perspective view of a preferred embodiment of a clamp assembly made according to the invention for securing a pair of tubular cylindrical bodies one of which is drawn in ghost outline with a first clasp in an unlatched position and a second clasp in a latched position;

FIG. 2 is a similar view to FIG. 1 showing the first clasp in a latched position and a second tubular cylindrical body drawn in ghost outline held by the second clasp forming part of the clamp assembly;

FIG. 3 is a top plan view of the clamp assembly of FIG. 2;

FIG. 4 is a side elevation view of the clamp assembly of FIG. 2;

FIG. 5 is a partly sectioned view of the clamp assembly of FIG. 1;

FIG. 6 is a partly sectioned view of the clamp assembly of FIG. 2;

FIG. 7 is a top view of the clasp forming part of the clamp assembly of FIG. 5 showing in ghost outline the location of a bolt in an access opening for a housing comprising the clasp;

FIG. 8 is a similar view to FIG. 7 showing the bolt captured in a peripheral groove for the housing;

FIG. 9 is a perspective view of the housing;

FIG. 10 is a cross-sectional view of the housing;

FIG. 11 is a top view of the housing showing in ghost outline a peripheral groove for capturing the bolt drawn adjacent the housing;

FIG. 12 is a bottom view of the housing showing a centre-line for an opening in the housing for receiving a post upon which the housing rotates and a centre-line for the post;

FIG. 13 is a similar view to FIG. 2 with a specialized latching tool engaged in the housing for the second clasp;

FIG. 14 is a similar view to FIG. 2 of a second embodiment of a clamp assembly made in accordance with the invention in which two clamps are rotatably coupled to each other;

FIG. 15 is a perspective view of a third embodiment of a clamp assembly made in accordance with the invention in which a single clamp is coupled to a holding ring for use as a fence clamp;

FIG. 16 is a perspective view of a fourth embodiment of a clamp assembly made in accordance with the invention in which the housing has a hexagonal shape;

FIG. 17 is a side elevation view of a housing for a clasp in accordance with the invention;

FIG. 18 is a top plan view of the housing of FIG. 17;

FIG. 19 is a bottom plan view of the housing of FIG. 17;

FIG. 20 is a cross-sectional view of the housing drawn on line A-A of FIG. 17 and showing a bolt in ghost outline received in a peripheral groove for the housing;

FIG. 21 is a perspective view of a fifth embodiment of a clamp assembly made in accordance with the invention incorporating the housing of FIG. 18 and showing a specialized tool;

FIG. 22 is a bottom plan view of the tool of FIG. 21;

FIG. 23 is a similar view to FIG. 22 showing the tool on the housing of FIG. 17; and

FIG. 24 is a perspective view of a sixth embodiment of a clamp assembly made in accordance with the invention showing a different style of hinge.

DESCRIPTION OF PREFERRED EMBODIMENT WITH REFERENCE TO DRAWINGS

Referring to FIGS. 1 and 2, there is illustrated a clamp assembly 20 made according to the invention for coupling first and second cylindrical bodies to each other, one of which is drawn in ghost outline and identified by reference numeral 22 in FIG. 1. The second cylindrical body is identified by reference numeral 23 in FIG. 2. The cylindrical body may be solid but, in this case, the cylindrical body is illustrated as tubular and is of the kind which is suitable for use in erecting a scaffold structure. The clamp assembly 20 consists of two clamps 24, 26 welded to each other in order to couple first and second tubular cylindrical bodies 22, 23 disposed orthogonally to each other. The first clamp 24 (drawn to the left of FIG. 1) is shown unlatched whereas the second clamp 26 is shown in a latched configuration. The component parts of the clamp 24, 26 are identical and therefore are identified by like numerals in the drawings.

The first clamp 24 will now be described in detail. It will be seen that the clamp 24 has a first curved body portion 28 and a second curved body portion 30 hinged to the first curved body portion 28 to form a generally circular enclosure for receiving the cylindrical body 22. Each of the first and second curved body portions 28, 30 are formed from a continuous loop of forged mild steel and they are coupled at one end of the clamp by a hinge 32 and at the other end by a releasably clasp 34. The radius of curvature of the first and second curved body portions 28, 30 is selected to approximate the outer diameter of the cylindrical body 22 received therebetween and additionally includes gripping portions on an interior surface thereof such as flat lands 36 cut from the steel for mating contact with the cylindrical body 22.

The hinge 32 has a C-shaped body with a medial separation 38 that spaces the first and second curved body portions 28, 30 with the respective continuous loops received in the C-shaped body so that each curved body portion may rotate in the C-shaped body independently of the other. In use, the medial separation 38 bears upon the cylindrical body 22 throughout its length thereby reducing the amount of bending moment on the hinge 32.

The clasp 34 consists of a bolt 40 fixed to the second curved body portion 30 with a mounting block 42 and a housing 44 that is rotatably coupled to the first curved body portion 28 with a mounting block 46 supporting a post 48.

The clamp assembly 20 is shown in a latched configuration in FIG. 2 to FIG. 4 and the operation of the clasp 34 will be described below with reference to FIGS. 5 to 8.

The structure of the housing 44 will now be described with particular references being made to FIGS. 9 to 12. In the embodiment illustrated, the housing 44 has a circular periphery. However, the external surface of the peripheral wall of the housing may also have other shapes such as the hexagonal shape shown in FIG. 16 or the fluted shape shown in FIG. 18. The top side of the housing 49 is circular and has an opening 50 formed therein for receiving the post 48. The opening 50 is eccentric to the geometric centre of the housing 44 for reasons that will be explained in more detail below.

The housing 44 has a peripheral wall 52 which depends from the top side 49 and that defines an access opening 54 through which the bolt 40 is received into the housing. A bottom lip 56 is co-extensive with the peripheral wall 52 and together they define a peripheral groove 58 for the housing which is adapted to capture the bolt 40 upon rotation of the housing 44. The housing 44 rotates as indicated by arrow 60 in FIG. 1 about the post 48. Since the opening 50 for receiving the post 48 is eccentric relative to the geometric housing 44, the passage formed between the peripheral groove 58 and the post 48 for receiving the bolt 40 varies in width about the periphery of the housing. As the passage becomes narrower increasing force is applied to secure the bolt 40 in the groove 58. Arrow 61 drawn in FIGS. 1, 5 and 6 shows the direction of the movement of the bolt 40 into the access opening 54 of the housing 44 when the second curved body portion of the clamp is moved in the hinge 32. It will be noted that the post 48 has a second access opening 62 which is aligned with the first access opening 54 in FIGS. 1 and 5 in order to receive the bolt 40 therein. On continued rotation of the housing 44 as indicated by arrow 60, the bolt is captured in the peripheral groove 58. The capture of the bolt 40 is also shown in the plan views of FIGS. 7 and 8.

In addition, it will be observed that the post 48 has a smaller diameter than the opening 50 and the centre-line of the post 48 is eccentric to the opening 50 to thereby further secure the clasp 34 and significantly minimize the likelihood of the clasp releasing during vibration of the clamp assembly 20.

As illustrated in FIG. 13 of the drawings, a specialized tool 64 may be used to engage the housing 44 for releasing the clasp 34 or tightening the clasp 34, as the case may be, to minimize tampering by those who do not have access to the tool.

In an alternative embodiment of the invention shown in FIG. 14, there is illustrated a clamp assembly 66 in which a pair of clamp bodies 24, 26 are rotatably coupled to each other with rotatable coupling 68 so that the relative orientation between the cylindrical bodies 22, 23 may be varied as indicated by arrow 70.

In yet another embodiment of the invention drawn in FIG. 15, a clamp assembly 74 is shown for use as a fence clamp in which there is a single clamp 24 which is rigidly coupled to a tube receiving member in the form of a ring 76 of fixed internal diameter.

In FIG. 16, it will be seen that the clasp housing 72 has a hexagonal shape so that a conventional wrench may be used to release or tighten the housing without the use of the specialized tool 64.

In use, the clamp assembly is positioned about a cylindrical body so that the cylindrical body is positioned between the first and second curved body portions 28, 30 of the clamp 24. The second curved body portion 30 is then brought into engagement with the cylindrical body 22 by aligning the bolt 40 with the receiving access opening 54 of the housing 44 and the second access opening 62 of the post 48. The housing 44 is then rotated so as to capture the bolt 40 in the peripheral groove 58 thereby securing the first and second curved body portions 28, 30 in frictional engagement with the cylindrical body 22.

It will be appreciated that the clamp assembly made according to the invention is more compact in size than prior art devices and therefore a large number of clamp assemblies may more easily be stored without accidental tangling of the assemblies with each other. The design of the first and second curved body portions 28, 30 allows the clamp 24, 26 to adjust for changes in the diameter of the enclosed cylindrical body 22, 23 so as to accommodate tubular scaffolding having different tolerances and originating from different sources having somewhat different diameters. In addition, the hinge 32 permits the first and second curved body portions 28, 30 to change their relative positions so as to enclose larger or smaller scaffolding tubes 22, 23 as the case may be. The compact design of the curved body portions 28, 30 results in less stretching of the material so that the clamp assembly will have a prolonged life. In the event that damage occurs to the housing 44, it may easily be replaced, particularly if the housing is attached to the second curved body portion 30 in the case of a dual clamp assembly so that it is independent of the second clamp forming part of the assembly 20.

Other variations to the clamp assemblies described may be made within the scope of the appended claims as will be apparent to those skilled in the art. In particular, the clasp comprising a bolt captured in a rotatable housing may be used to secure first and second body portions having different configurations than those shown in the accompanying drawings.

Advantageously, the housing for the clasp has a peripheral wall 77 with a fluted external surface 78 as illustrated in FIGS. 17 to 21 where the housing is designated by reference numeral 80 in a clamp assembly 82. The internal surface 84 of the peripheral wall 77 is scalloped (see FIGS. 19 and 20) and has a radius of curvature which will allow the bolt 40 to nest inside the scallops as shown in FIG. 20 for a stepwise adjustment of the clasp.

Like the housing 40, an access opening 54 is formed in the peripheral wall 77 to allow the bolt 40 to be introduced into the housing and a bottom lip 56 which is co-extensive with the peripheral wall 77 defines a peripheral groove 50 for the housing 80 in order to capture the bolt 40 upon rotation of the housing 80.

In the embodiment illustrated, the housing 80 has a circular opening 86 formed in a top side of the housing which is positioned in a quadrant of the housing to receive the post 48. As a result, the passage formed between the peripheral groove 58 and the post 48 is wider on one side of the access opening 54 than the other. Thus, rotation of the housing 80 in the direction indicated by arrow 88 in FIG. 20 will operate to release the clasp whereas rotation in the opposite direction will tighten the clasp.

A specialized tool 90 is shown in FIG. 21 for releasing and tightening the housing 80. It consists of a handle 92 for leverage and a cup 94 at one end of the handle 92 having an internal surface 96 with a shape made to cooperate with the fluted external surface 78 of the housing 80 as shown in FIG. 23. Conveniently, the peripheral wall of the cup 94 operates to block the access opening 54 (see FIG. 23) so that the bolt 40 cannot inadvertently emerge from the access opening 54. This feature allows the tool 90 to release the clasp in order to reposition the clamp “on the fly”, that is, on location, with a reduced need to be concerned about an associated scaffold structure becoming disengaged from the clamp.

It will be observed in FIG. 21 that the clamp assembly 82 features a different style of hinge 98 with a more angular C-shaped body formed by upper and lower flanges 100, 102 disposed on opposite sides of the hinge body.

A smoother, rounder profile for the flanges 104, 106 is shown by the hinge 108 in FIG. 24 which are disposed on opposite sides of a rounded hinge body.

Still other variations to the clamp according to the invention will equally be understood to be within the scope of the appended claims. 

1. A clamp for securement to at least one cylindrical body, the clamp comprising: a first curved body portion, a second curved body portion hinged to the first curved body portion to form a generally circular enclosure for receiving the cylindrical body, and a clasp for releasably coupling said first and second curved body portions, the clasp having a bolt fixed to one of said first and second curved body portions, and a rotatable housing defining a peripheral groove for slidingly receiving said bolt coupled to the other of said first and second curved body portions, the housing having an access opening for receiving the bolt into said peripheral groove and being adapted to capture the bolt in said groove upon rotation of the housing thereby securing said first and second curved body portions in frictional engagement with said cylindrical body.
 2. Clamp according to claim 1 in which the housing is rotatable about a post fixed to the other said first and second curved body portions, the housing having an opening for receiving the post that is eccentric to the geometric centre of the housing so that a passage formed between the peripheral groove and the post varies in width about the periphery of the housing.
 3. A clamp according to claim 2 in which the post is circular and has a diameter commensurate with the diameter of the opening in the housing.
 4. A clamp according to claim 3 in which the post has a smaller diameter than the diameter of the opening in the housing, the opening in the housing being eccentric relative to the geometric center of the post.
 5. A clamp according to claim 1 in which the first and second curved body portions are each formed from a continuous loop forged from mild steel.
 6. A clamp according to claim 5 in which the first and second curved body portions each have gripping portions shaped from the continuous loop on an interior surface thereof for mating contact with a cylindrical body received in the clamp.
 7. A clamp assembly for coupling first and second cylindrical bodies to each other having a clamp according to claim 1 and a tube receiving member shaped to receive said second cylindrical body, the tube receiving member being coupled to the first curved body portion of said clamp.
 8. A clamp assembly according to claim 7 in which the tube receiving member is a second clamp comprising: a first curved body portion, a second curved body portion hinged to the first curved body portion to form a generally circular enclosure for receiving the cylindrical body, and a clasp for releasably coupling said first and second curved body portions, the clasp having a bolt fixed to one of said first and second curved body portions, and a rotatable housing defining a peripheral groove for slidingly receiving said bolt coupled to the other of said first and second curved body portions, the housing having an access opening for receiving the bolt into said peripheral groove and being adapted to capture the bolt in said groove upon rotation of the housing thereby securing said first and second curved body portions in frictional engagement with said cylindrical body.
 9. A clamp according to claim 7 in which the tube receiving member is rotatably coupled to the first curved body portion.
 10. A clamp assembly according to claim 9 in which the tube receiving member is a second clamp comprising: a first curved body portion. a second curved body portion hinged to the first curved body portion to form a generally circular enclosure for receiving the cylindrical body, and a clasp for releasably coupling said first and second curved body portions, the clasp having a bolt fixed to one of said first and second curved body portions, and a rotatable housing defining a peripheral groove for slidingly receiving said bolt coupled to the other of said first and second curved body portions, the housing having an access opening for receiving the bolt into said peripheral groove and being adapted to capture the bolt in said groove upon rotation of the housing thereby securing said first and second curved body portions in frictional engagement with said cylindrical body.
 11. A clamp assembly according to claim 7 in which the rotatable housing of the clamp is rotatable about a post fixed to the second curved body portion of the clamp to facilitate replacement of spare parts.
 12. A clamp according to claim 1 in which the housing has a peripheral wall with a hexagonal external surface to facilitate tightening and release of the housing from the bolt using a conventional wrench.
 13. A clamp according to claim 1 in which the housing has a peripheral wall with a fluted external surface to facilitate tightening and release of the housing from the bolt using a specialized tool.
 14. A clamp according to claim 1 in which the housing has a peripheral wall with a scalloped internal surface for step-wise adjustment of the clasp.
 15. A clamp according to claim 5 having a hinge to couple said first and second curved body portions, the hinge having a C-shaped body with a medial separation spacing said first and second curved body portions with the respective continuous loops received in said C-shaped body so that each said curved body portion may rotate in the C-shaped body independently of the other. 